1. Field of the Invention
The present invention relates in general to the field of information handling system displays, and more particularly to a system and method for portable information handling system integrated backlight control.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Information handling systems configured as portable units have grown in popularity among users over the past several years. Portable information handling systems generally integrate in a single housing a display, internal power source and processing components, such as the CPU and hard disk drive, so that a user can carry the portable system from place to place while the system is operating. As processing components have decreased in size and increased in performance, portable information handling systems are often able to pack processing capabilities into a relatively small housing that are comparable to the capabilities available from desktop systems. One important consideration to achieving portability is reducing the power consumption of the components within the system so that the internal power will support operations for a long enough time period. Generally the most practical display solution for portable systems both in terms of size and power consumption are liquid crystal display (LCD) panels. LCD panels have a backlight, such as cool cathode florescent light (CCFL), that illuminates through a panel of pixels. An image is generated by altering the light-absorbing characteristics of the pixels so that backlight passing through a pixel has a desired color.
Although LCD panels provide an effective display solution for portable information handling systems, manufacturers still typically seek to reduce power consumption by the LCD panels as much as possible while presenting quality images from the panels. One example of an attempt to maintain display quality with reduced power consumption is the Display Power Saving Technology (DPST) available with Intel chipsets. DPST attempts to maintain the visual experience of a display with reduced backlight illumination by altering the image brightness and contrast for the colors within an image. A graphics processing unit (GPU) provides incremental DPST adjustments to an inverter that powers the backlight so that the adjustments are not perceptible by a user. Users typically select the level of brightness for a display with manual inputs through a keyboard and that level of brightness is maintained relative to environmental conditions with an ambient light sensor (ALS) located in the panel. An embedded controller (EC) generally located in the base of the display accepts user inputs and ALS measurements to manage inverter output. However, the bus from the EC to the GPU and inverter is typically a single channel, such as a pulse width modulation (PWM) bus or an SMBus. Managing the adjustments to brightness by both the DPST and ALS through a common bus adds significant complexity to the generation of displays through analog to digital channels, processing, physical interface considerations and EC design and layout. Often substantial EC workloads impact display quality with delays also introduced by the narrow communication channel from the EC to the GPU.